Revert "[Runtimes] Merge 'compile_commands.json' files from runtimes build (#116303)"

This reverts commit 054f914, which was
found to break the runtimes build.

Author: ldionne

llvm/utils/merge-json.py

@@ -346,21 +346,3 @@ if(SUB_COMPONENTS)
       ${CMAKE_CURRENT_BINARY_DIR}/runtimes/Components.cmake)
   endif()
 endif()
-
-# If the user requested 'compile_commands.json' we merge the generated JSON from
-# the created directories.
-if(CMAKE_EXPORT_COMPILE_COMMANDS)
-  # Make a dependency so that we don't error if the file gets deleted somehow.
-  add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/compile_commands.json
-                     COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_BINARY_DIR}/compile_commands.json)
-
-  file(TO_NATIVE_PATH "${LLVM_MAIN_SRC_DIR}/utils/merge-json.py" MERGE_JSON_PATH)
-  add_custom_command(OUTPUT ${LLVM_BINARY_DIR}/compile_commands.json
-                     COMMAND ${CMAKE_COMMAND} -E touch ${LLVM_BINARY_DIR}/compile_commands.json
-                     COMMAND ${Python3_EXECUTABLE} ${MERGE_JSON_PATH}
-                             ${LLVM_BINARY_DIR}/compile_commands.json
-                             ${CMAKE_BINARY_DIR}/compile_commands.json
-                             -o ${LLVM_BINARY_DIR}/compile_commands.json
-                     DEPENDS ${CMAKE_BINARY_DIR}/compile_commands.json)
-  add_custom_target(merge_runtime_commands ALL DEPENDS ${LLVM_BINARY_DIR}/compile_commands.json)
-endif()